1. Field of the Invention
The present invention relates to the field of photography and, more particularly, to apparatus for laminating or bonding a transparent protective cover sheet to an image-bearing surface of a photograph.
2. Description of the Prior Art
The present invention provides an apparatus for bonding or laminating a transparent cover sheet to the image-bearing surface of a photograph or positive photographic print, preferably of the type prepared by a diffusion transfer process in a self-developing film unit.
The print may have a silver image (black and white) or a dye image (color), and the transparent cover sheet preferably is of the type having a thin layer of a fluid-activatable bonding agent on one side thereof which becomes wetted by an appropriate activating fluid during the course of the laminating process and is brought into face-to-face contact with the image-bearing surface of the print to effect the bond and thereby form a laminated structure.
With certain types of black and white self-developing film units, for example the type described in U.S. Pat. No. 2,543,181 issued on Feb. 27, 1951 to E. H. Land, it is recommended that the image bearing surface of the photograph should be "washed" and covered with a transparent layer soon after processing to improve long-term image stability. The "washing" (or cleaning) refers to applying a fluid to the surface under pressure, such as by gently wiping or rubbing, to remove or neutralize small amounts of residual processing composition which may tend to oxidize or otherwise adversely effect the silver image. The covering of the image bearing surface with a transparent layer improves image stability by substantially isolating the silver image from oxidizing agents that may be present in the atmosphere. For a representative example of a process wherein the image bearing surface of a photograph is "washed" and covered with a thin transparent plastic cover sheet to form a laminate, see U.S. Pat. No. 2,798,021 issued to E. H. Land on July 2, 1957.
In applications where the black and white or color photograph is used to form part of an identification card or I.D. credit card which includes, for example, an image of the bearer and other information thereon, the transparent cover serves as a tamperproof security seal in that after the cover sheet is bonded to the image-bearing surface it cannot be removed without damaging or destroying the image. In such applications, the cover sheet also serves to improve print stability when the photograph is produced from the previously described type of black and white film unit that requires such a post-processing protective covering. For representative examples of such identification card laminate structures, reference may be had to U.S. Pat. Nos. 3,313,052; 3,511,655; 3,581,416; 3,647,442; 3,644,116; and 3,827,726.
While the previously described laminates may be formed manually using a hand-held roller to distribute the activating fluid between the bonding agent layer of the cover sheet and the image-bearing surface of the superposed photograph while applying pressure to urge the two sheets into bonding contact (as suggested in U.S. Pat. No. 2,798,021), it is preferably to have a laminating apparatus or machine for automatically performing the laminating task in applications where there are large quantities of photographs or prints that require such protection.
U.S. Pat. Nos. 3,438,835 and 3,543,662 disclose apparatus for automatically laminating a transparent cover sheet to the image-bearing surface of a diffusion transfer print. The laminator includes a support member for rotatably mounting an elongated web roll of a transparent plastic material, having a fluid-activatable bonding agent on one side, which is fed between a pair of pressure rollers with a print having a "wet" image-bearing surface in facing relation to the bonding agent to form the laminate. The rollers also include a severing device for cutting the plastic web to separate the laminate from the web following the bonding operation.
While such apparatus function in a satisfactory manner, they do have the disadvantage of including a web-severing device which is subject to wear and must be serviced at regular intervals to insure that the cutting edges are sharp and properly aligned.
Therefore, it is an object of the present invention to provide a compact and simply constructed laminating apparatus for automatically laminating or bonding a transparent cover sheet to the image-bearing surface of a photograph or photographic print without requiring the severing or cutting of any of the materials used in the laminating process.
It is another object of the invention to provide an automatic laminating apparatus for bonding a transparent cover sheet having a fluid-activatable bonding agent on one side thereof to the image-bearing surface of a print wherein the activating fluid is applied to the image-bearing surface to provide some beneficial washing action of this surface to improve print stability by substantial removing or neutralizing residual processing composition therefrom if the same is present and/or to improve the quality of the laminate by removing dust or dirt from the surface.
Other objects will in part be obvious and will in part appear hereinafter.